In the making of glass a very large amount of heat is needed to melt the glassmaking materials as they are processed in a glassmelting furnace. Generally this heat is provided by the combustion of fuel and oxidant which has heretofore generally been air.
Nitrogen oxides (NOx) are recognized pollutants and it is desirable to reduce emissions of NOx from industrial processes. NOx is produced in air-based combustion mainly because at the high temperatures of the combustion reaction, nitrogen from the air combines with oxygen.
Recently in response to the NOx problem many industrial processes have begun using pure oxygen or oxygen-enriched air to carry out the combustion as this reduces or completely eliminates the nitrogen brought into the area of the combustion reaction by the oxidant.
In the processing of glassmaking materials such as in a glassmaking furnace, while the use of oxygen or oxygen-enriched air has indeed served to reduce the NOx emissions over what would have been expected if air were the oxidant, the reduction in NOx generation has not been as great as should be expected when the batch materials contained niter.
Accordingly, it is an object of this invention to provide a method for processing glassmaking materials with reduced emissions of nitrogen oxides.